Article conveyor system

ABSTRACT

A conveyor system for moving large quantities of articles through relatively small tunnels prevents blocking of restricted passages or tunnels by the articles by including a pair of belts in side-by-side relation with each other, and intermittently halting the belts individually during their movement, with one belt continuing to move while the other is halted. Preferably the tunnel sides taper slightly outwardly from the inlet portal to the outlet portal which is correspondingly wider than the inlet portal, and the upper article-supporting surface of the belts are roughened to enhance frictional engagement with the supported articles. The belts may consist of short molded sections each having an integral sprocket chain link formed on its underside and pinned to the link part of the adjacent sections. For use in electrical treating apparatus, the belt sections are of dielectric material and may be perforated extensively. The belts are driven by a pneumatic cylinder and piston assembly through a one-way clutch so that if either belt becomes jammed, it can fully stop during the power stroke of its piston, and will be free to move rearwardly to relieve the jam during the reverse stroke of its piston.

United States Patent 1 Williams 1 Mar. 27, 1973 [54] ARTICLE CONVEYORSYSTEM [76] Inventor: Ralph L. Williams, 3609 Manhattan, Maplewood, Mo.63143 221 Filed: May 19,1971

21 Appl. No.: 144,758

[52] U.S. Cl 198/76, 198/198 [51] Int. Cl.....; ..B65 g 37/00 [58] Fieldof Search '....l98/7'6, 75, 195, 198; 141/99,

[56] References Cited UNITED STATES PATENTS 1,482,467 2/1924 Harrington..l4l/l90 X 2,628,010 2/1953 1,528,357 3/1925 2,784,835 3/1957 3,055,4889/1962 3,389,777 6/1968 FOREIGN PATENTS OR APPLICATIONS 959,897 3/1957Germany ..l98/l98 Primary Examiner-Richard E. Aegerter AssistantExaminerl-ladd S. Lane Att0meyBedell and Burgess [57] ABSTRACT Aconveyor system for moving large quantities of articles throughrelatively small tunnels prevents blocking of restricted passages ortunnels by the articles by including a pair of belts in side-by-siderelation with each other, and intermittently halting the beltsindividually during their movement, with one belt continuing to movewhile the other is halted.- Preferably the tunnel sides taper slightlyoutwardly from the inlet portal to the outlet portal which iscorrespondingly wider than the inlet portal, and the upperarticle-supporting surface of the belts are roughened to enhancefrictional engagement with the supported articles. The belts may consistof short molded sections each having an integral sprocket chain linkformed on its underside and pinned to the link part of the adjacentsections. For use in electrical treating apparatus, the belt sectionsare of dielectric material and may be perforated extensively. The beltsare driven by a pneumatic cylinder and piston assembly through a one-wayclutch so that if either belt becomes jammed, it can fully stop duringthe power stroke of its piston, and will be free to move rearwardly torelieve the jam during the reverse stroke of its piston.

16 Claims, 7 Drawing Figures ARTICLE CONVEYOR SYSTEM BACKGROUND OF THEINVENTION 1. Field of the Invention The invention relates to beltconveyor systems and more particularly to a conveyor for quantities ofarticles constructed to prevent blocking of restricted passageways bythe articles.

2. The Prior Art Conventional conveyor systems utilize a single belt formoving articles deposited haphazardly on the belt frequently becomeblocked by the articles if the conveyor passes through a restrictedpassage such as a tunnel.

SUMMARY OF THE INVENTION The invention provides a conveyor system forthreedimensional articles in which jamming of the articles in restrictedpassageways such as tennels is prevented by utilizing a pair of conveyorbelts in side-by-side relation and having their driving meansconstructed to halt the individual belts intermittently, with one beltcontinuing to move while the other is halted. The invention includesmeans for freeing either belt to halt or' move rearwardly in the event ajam occurs, so as to prevent damage to the apparatus and relieve thejam. Additional objectives include the provision of one-piece moldedbelt sections each incorporating an integral sprocket chain-link, theprovision of a dielectric belt suitable for electric treating apparatus,the arrangement of a conveyor belt tunnel to enhance the effect of thedual belts and reduce the likelihood ofjamming.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational viewpartially sectionalized of apparatus incorporating the invention.

FIG. 2 is an enlarged top view, partially sectionalized of the apparatusillustrated in FIG. 1.

FIG. 3 is a top view partially sectionalized of a por-' tion of aconveyor belt constructed in accordance with the invention.

FIG. 4 is an enlarged elevational view of a portion of the conveyor beltof FIG. 3 and one of the sprockets.

FIG. 5 is a transverse vertical sectional viewalong line 5-5 of FIG. 4.

FIG. 6 is a longitudinal vertical sectional view alon line 66 of FIG. 5.3

FIG. 7 is a schematic view of the electro-pneumatic control system.

DESCRIPTION OF THE PREFERRED EMBODIMENT The numeral 1 refers to abox-like housing for apparatus, which may be of the type disclosed in myU.S. Pat. No. 3,484,363 for electrically treating plastic bottles andthe like, and which includes a tunnel 3 through which the bottles mustpass for treatment.

Tunnel 3 has a relatively narrow inlet portal 5 and a slightly wideroutlet portal 7, to reduce the likelihoof of the bottles or otherarticles jamming as they are moved through the tunnel.

For moving the articles through the tunnel expeditiously and avoidingany interference with electrical treatment effected vertically throughthe tunnel, a conveyor comprising a pair of endless belts 9L and 9Rpasses through the tunnel, over independent driving sheaves or sprockets11R and 11L at the outlet end, under bottom idler sprockets 13L and 13Rnear the base of apparatus 1, and over inlet idler sprockets 15L and 15Rat the inlet end of the tunnel.

- Belts 9L and 9Rare formed of Hard dielectric plastic material in shortsections approximately equal in length to the circular pitch of thesprockets. Each section includes an upwardly facing plate 17 perforatedby closetom surface of each plate 17 is formed with closed pintle chainlinks comprising'a pair of transversely spaced longitudinally extendingribs 23, bent toward each other such that their inner vertical surfacesat one end 24 are spaced apart transversely a slightly greater distancethan their outer surfaces at the other end 25. At their closely spacedends, ribs 23 are connected by a hollow transverse cylindrical member 27which forms a pintle for engagement with the sprocket teeth and bothends of each rib are pierced with transversely aligned pairs of holes 29and 30 spaced apart the same distance as the circular pitch of thesprockets. Pins 31 of the same material as the belt sections passthrough the aligned holes 29 and 30 in adjacent ends of the links formedby ribs 23 to couple the links and associated belt section platestogether while accommodating their articulation. I v

For driving drive sprockets 11R and 11L independently of each other suchthat one may rotate while the other is halted and vice versa, the drivesprocket bracket, mounts individual drive mechanism at each side of theconveyor, the mechanisms are identical and each comprises adouble-acting pneumatic cylinder 35 having its piston rod 37. extendingparallel to the con? veyor. Piston rod 37 mounts a toothed rack 39,which meshes witha pinion 41. The latter incorporates a oneway clutch 43mounted on one of the drive sprocket shafts 12L or 12R such thatmovement of piston [@437 and rack 39 to the right and consequentclockwise movement of its pinion 41 will produce clockwise movement ofthe associated sprocket shaft 12L or 12R and the sprocket 12L or 12Rmounted thereon, which movement will cause advancing or leftwardmovement of the corresponding conveyor belt 9L or 9R into and throughtunnel 3, while movement of piston rod 37 and rack 39 to the left andconsequent counterclockwise movement of pinion 41 will produce nomovement of the associated sprocket shaft or sprocket and so that, inthe event ofajam in the tunnel, the forward movement of the jammed beltwill cease even though the associated piston rod is in its power stroke,because of the compressibility of the air, and, as soon as the pistoncommences its reverse stroke, tension in the jammed belt will pull thebeltrearwardly to relieve the jam. Accordingly the movement of each belt9L and 9R will be intermittent, advancing during outward movement of theassociated piston rod 37 and halted during inward movement of the pistonrod.

For simultaneously actuating cylinders 35].. and 35R in oppositedirections and controlling the velocity of their piston rods 37, anelectrical control system, as shown schematically in FIG. 7, may beprovided. The system comprises a source 45 of AC power, connected byconductors 47 and 49 to the primary winding of a variable transformer51, the secondary winding of which is connected by conductors 53 and 55to a rectifier 59. The output of rectifier 59 is fed by conductors 61and 63 to DC motor 65 so that the speed of the latter is proportional tothe variable output of transformer 51 and is thus controllable thereby.Shaft 67 of motor 65 mounts a contact arm 69 on its end for alternateengagement with microswitches 71L and 71R, which are supplied withalternating current from source 45 by conductors 73. Microswitches 71Land 71R are connected respectively by conductors 75L and 75R to solenoidvalves 8lL'and 81R,,so as to selective ly energize them, their circuitbeing completed by con ductor 83 leading to the AC power source 45.

A source of compressed air including conduit85 is connected to valves81R and 81L, each of which has an exhaust outlet 87 and conduitconnections 89L, 89R to the rear end of the respective cylinder andconduit connections 91L, 91R to the forward end of the respectivcylinder.

Both valves8lL' and 81R are normally set to provide communicationbetween air supply conduit 85 and conduits 91L and R when the electircalsystem is not energized, thus maintaining piston rods 37L and R in theextended position shown in the drawings. Upon alternate energization ofthe valve solenoids resulting from alternate closure of microswitches71L and 71R,

' conduits 91L and 91R are alternately closed and conduits 89R and 89Lare opened, alternately retracting piston rods 37L and 37R.

I As piston rods 37L and 37R are alternately retracted, their retractingmovement is not transmitted to their respective sprockets 11L or 11Rbecause of the action of one-way clutches 43 in pinions 41. Hence,during the alternate retractive movements of the piston rods, the belts9L and 9R are alternately stopped, while the alternating extendingmovements of the piston rods are transmitted by racks 39, pinions 41,clutches 43 and shafts 1,2 to drive sprockets 11L and 11R, to drivebelts 9L and 9R forward alternately.

The frequency of the alternate interruptions of belts 9L and 9R can beselectively varied by using variable transformer 51 to vary the ACvoltage supplied to rectifier 59 and the DC voltage supplied by thelatter to DC motor 65. As the voltage is reduced, the speed of motor 65is correspondingly reduced, as is the frequency of alternate closure ofmicroswitches 71L and 71R and of operation of valves 81L and 81R.

Preferably valves 81L and 81R are calibrated so that the belt advance orextending movement of the piston latter, conductor 75L is energized,connecting conduit 89L to exhaust outlet 871.. and connecting conduit91L to sir supply conduit 85, thereby causing piston rod 37L to retract,during which movement of the piston rod sprocket 11L and belt 9L remainstationary because of the action of one-way clutch 43L. Upon completionof the forward piston stroke and opening of microswitch 71L as motor arm69 rotates, valve 81L connects conduit 91L to exhaust outlet 87L andconnects air supply conduit 85 to conduit 91L, thereby projecting pistonrod 37L, and through rack 39L, pinion 41L,'clutch 43L and shaft 12Ldriving sprocket 11L clockwise (from the viewpoint of FIG. 1) andthereby advancing belt 9L until piston rod 37L reaches the outer end ofits stroke.

' During the operation of the left-hand side of the conveyor, describedabove, piston rod 37R has been in the projected position and remainsthere, with no movement of belt 9R. As soon as arm 69 on DC motor shaft67 engages microswitch 71R the solenoid of valve 81R is energized,causing valve 81R to vent air conduit 91R to exhaust and connectairconduit 89R to air supply line 85, causing retraction of piston rod 37R,but no position, exhausting air conduit 89R and connecting conduit 91Rto air supply line 85 and thereby projecting piston rod 37R at apredetermined slow speed, to drive sprocket 11R and advance belt 9R at aproportionate speed. As DC motor 65 continues to rotate, alternatelyactuating microswitches 71L and 71R, belts 9L and 9R will alternatetheir advances and interruptions. Assortments of objects, such asplastic bottles B fed haphazardly onto the adjacent inlet end of belts9L and 9R will be propelled through tunnel 3 by the belts. In the eventof a blockade by .a jumble of the bottles,

' the movement of one belt while the other is stopped, as

described above, will tend to move any bottles cross- ;ways ofthetunniel to a diagonal or axial position, thus releasing the blockage.Particularly stubborn bottles will be engaged by pins 22 and thusbepropelledto a nonblocking position. The increasing width of tunnel 3from inlet to outlet will also facilitate the clearance of blockades. Inthe eventthat this fails to break the blockade, the moving belt can stopeven though the piston is in its power stroke because of thecompressibility of the air in the cylinder, and as soon as theassociated piston rod commences its reverse stroke, because the theassociated one-way clutch, the jammed belt will be free to moverearwardly responsive to its own tension, to free the articles from theblockade, after which the normal cycle of operation will resume.

Details of the conveyor system disclosed herein may be variedsubstantially without departing from the spirit of the invention and theuse of' such modifications as come within the'scope of the appendedclaims is contemplated.

1 claim:

1. An article conveyor system comprising a pair of belts inside-by-siderelation, means for drivingsaid belts separately from each other withalternating interruptions and advances of each belt with respect to'theother, and a tunnel forming a passageway for said belts and having inletand outlet portals, said outlet portal being larger than said inletportal and said tunnel tapering outwardly from its inlet to its outletend.

2. An article conveyor system according to claim 1 wherein thetransverse dimension of said outlet portal is greater than that of saidinlet portal and the sides of said tunnel are correspondingly taperedoutwardly from their inlet to outlet ends.

3. An article conveyor system according to claim 1 wherein saidbelt-driving means comprises a pair of pneumatic motors, separatedriving sheaves, operative connections between said motors and saiddriving sheaves respectively.

4. An article conveyor system according to claim wherein said motorscomprise double-acting pneumatic cylinders and said operativeconnections comprise racks driven by said cylinders, pinions meshingwith said racks, and means for transmitting rotary motion from saidpinions respectively to said driving sheaves in one direction only. 1

5. An article conveyor system according to claim 4 including means foralternately reversing the direction of said racks.

6. An article conveyor system according to claim 5 including'a source ofcompressed air, said reversing means valve means connected to saidsource and having separate connections to the opposite ends of saidcylinders.

7. An article conveyor system according to claim 6 including controlmeans for actuating said valve means to' alternately reverse the airconnections to said cylinders.

8. An article conveyor system according to claim 7 in which said controlmeans includes a source of electric energy and said valve means iselectrorespon sive.

eluding solenoid actuators, said valves being connected respectively tosaid cylinders, said control means being connected to said solenoidactuators and including means for alternately energizing them.

10. An article conveyor system according to claim 8 wherein said valvesnormally conn ect said air source to the ends of said cylinders toadvance said belts, said solenoid actuators alternately causing saidvalves to connect said air source to the end of said cylinders tointerrupt said belts alternately.

11. An .article conveyor system according to claim 1 wherein saiddriving sheaves are sprockets and said belts mount elements on theirunderside matingly engageable with the teeth of said sprockets.

12. An article conveyor system according to claim 1 1 wherein said beltsare in short sections each comprising a rectangular plate formed with apintle chain link on their undersides, there being pintle elementsconnecting said plates to each other and accommodating theirarticulation around said sprockets.

13. An article conveyor system according to'claim 12 wherein the uppersurfaces of said plates are formed with a plurality of small bosses forfrictional engagement with articles carried by the conveyor.

14. An article conveyor system according to claim l3 wherein some ofsaid plates mount upstanding pins for propelling engagement witharticles carried by the coni i An article conveyor system according toclaim 13 wherein said plates are extensively perforated.

16. An article conveyor system according to claim 15 includingupstanding pins fitted into some of said plate perforations.

1. An article conveyor system comprising a pair of belts in side-by-siderelation, means for driving said belts separately from each other withalternating interruptions and advances of each belt with respect to theother, and a tunnel forming a passageway for said belts and having inletand outlet portals, said outlet portal being larger than said inletportal and said tunnel tapering outwardly from its inlet to its outletend.
 2. An article conveyor system according to claim 1 wherein thetransverse dimension of said outlet portal is greater than that of saidinlet portal and the sides of said tunnel are correspondingly taperedoutwardly from their inlet to outlet ends.
 3. An article conveyor systemaccording to claim 1 wherein said belt-driving means comprises a pair ofpneumatic motors, separate driving sheaves, operative connectionsbetween said motors and said driving sheaves respectively.
 4. An articleconveyor system according to claim 3 wherein said motors comprisedouble-acting pneumatic cylinders and said operative connectionscomprise racks driven by said cylinders, pinions meshing with saidracks, and means for transmitting rotary motion from said pinionsrespectivelY to said driving sheaves in one direction only.
 5. Anarticle conveyor system according to claim 4 including means foralternately reversing the direction of said racks.
 6. An articleconveyor system according to claim 5 including a source of compressedair, said reversing means valve means connected to said source andhaving separate connections to the opposite ends of said cylinders. 7.An article conveyor system according to claim 6 including control meansfor actuating said valve means to alternately reverse the airconnections to said cylinders.
 8. An article conveyor system accordingto claim 7 in which said control means includes a source of electricenergy and said valve means is electroresponsive.
 9. An article conveyorsystem according to claim 8 wherein said valve means comprises a pair ofvalves including solenoid actuators, said valves being connectedrespectively to said cylinders, said control means being connected tosaid solenoid actuators and including means for alternately energizingthem.
 10. An article conveyor system according to claim 8 wherein saidvalves normally connect said air source to the ends of said cylinders toadvance said belts, said solenoid actuators alternately causing saidvalves to connect said air source to the end of said cylinders tointerrupt said belts alternately.
 11. An article conveyor systemaccording to claim 1 wherein said driving sheaves are sprockets and saidbelts mount elements on their underside matingly engageable with theteeth of said sprockets.
 12. An article conveyor system according toclaim 11 wherein said belts are in short sections each comprising arectangular plate formed with a pintle chain link on their undersides,there being pintle elements connecting said plates to each other andaccommodating their articulation around said sprockets.
 13. An articleconveyor system according to claim 12 wherein the upper surfaces of saidplates are formed with a plurality of small bosses for frictionalengagement with articles carried by the conveyor.
 14. An articleconveyor system according to claim 13 wherein some of said plates mountupstanding pins for propelling engagement with articles carried by theconveyor.
 15. An article conveyor system according to claim 13 whereinsaid plates are extensively perforated.
 16. An article conveyor systemaccording to claim 15 including upstanding pins fitted into some of saidplate perforations.